Engine Management Warning Light

[Nutshell]

The handbook calls it the "Malfunction Indicator Lamp", it's the one shaped like an engine and tells you there's something wrong with the Engine Management Unit...

It came on around 70k miles and my dealer switched it off when I had it serviced. It came on again at 74k and I paid him to switch it off again. It came on again today and I'm fed up with paying to have a light switched off!

The car is running fine, fuel consumption is OK (30 - 32 mpg). The only clue that something may be wrong was at the MOT test when the exhaust emission was just in limits when it should have been well inside.

The oil level warning light also comes on and goes off at random. I check the oil level and it's full, hasn't used a drop.

Has any of this happened to anyone else? Any clues about what the problem might be?

Is there a way to switch the engine warning light off without paying my dealer to do it?

[Bazza]

could be a lamba sensor sensing high emmissions

allways try disconnecting the Battery for ten minutes - should reset everything

[dlayen]

Is there a way to switch the engine warning light off without paying my dealer to do it?

take the lamp out

[GreyBeard]

but when the light's on, assuming it's switched on by the computer and not by a wiring malfunction, then it also shuts down some of the 'fine tuning' of the engine which usually results in significantly lower performance. so removing the bulb (even if this were possible) would make no difference!

[ColinBarber]

You need to get the error code stored in the ECU. The light will come on for hundreds of reasons so until you know the error code(s) it's just a guess as to what is wrong.

You need to plug a ODB-II scan tool into the diagnostic socket to retreive the code(s).

[Steve ( West Mids )]

First job if you can't get the code - replace the sensor. It can muck up the cat. if emissions are wrong.

[yemgi]

could be a lamba sensor sensing high emmissions

allways try disconnecting the battery for ten minutes - should reset everything

That is what I did on mine, I had a crap soldering point on the lambda sensor after the main cat fixed since then, but disconnecting the Battery fo 1 min was enough to reset the light ;)

[Nutshell]

How did you work out it was a bad solder joint???? Was it just by inspection?

I've checked the two front lambda sensors and they seem to be doing their stuff, but the one behind the main cat means jacking up the car so I haven't checked that one yet.

Lexus want around £140 for a new sensor. Are they the same as Toyota's? They have the same wires.

[ColinBarber]

Most sensors are the same.

[yemgi]

How did you work out it was a bad solder joint???? Was it just by inspection?

I did cut the loom for some reasons and had problems with one of the wires where solder wasn't great. After a few check engine lights goes on, I resoldered it and never get the light turn on again ;)

[Nutshell]

Ah, OK, I won't go looking for a bad solder joint then! :mat:

I've just been trying to remove the lambda sensor after the main cat to check it's OK but can't find a way to get it off. The cable goes into the body in the tunnel somewhere around the passenger seat rear mounting. I thought it went into the center console and I've had all that out (thanks LOC, I couldn't do it without you! :D ), but I can't find the cable anywhere.

Does anyone know how to disconnect this lambda sensor so I can remove it?

I also checked the air filter and it was full of rubbish. I'll replace it anyway (it's not due for another 12k miles) but could this have been the cause of the warning light?

It's ages since I've had to tinker with a car as much as this one, but it's really well designed and I'm quite impressed!